The Associations of Shift Work, Sleep Quality, and Incidence of Hypertension in Ontario Adults: A Population-Based Study

Relatively few population-based studies have explored the relationship and potential mechanisms between exposure to shift work and hypertension. The study objectives for this study were to determine 1) if history of shift work was associated with increased rates of hypertension among working adults, and 2) if sleep quality mediated this relationship. We conducted a population-based cohort study using data from Ontario respondents (aged 35-69 y) in the 2000-2001 Canadian Community Health Survey, which was linked to administrative health data housed at the Institute for Clinical Evaluative Sciences. Our sample included survey participants who were employed with no previous diagnosis of hypertension (n = 7420). During a 12-year follow-up window, we determined the time of hypertension diagnosis based on a previously validated algorithm; and explored the mediating effect of sleep quality using marginal structural effect models. The study sample included 2079 shift workers and 5341 day workers. Shift workers reported less refreshing sleep, more trouble sleeping, and poorer sleep quality overall compared with day workers. In 12 years of follow-up, 31.3% of workers developed hypertension. History of shift work was associated with higher hypertension rates in both men (hazard ratio [HR] 1.21, 95% confidence interval [CI] 1.02-1.44) and women (HR 1.26, 95% CI 1.03-1.55). There was no evidence that these associations were mediated by past sleep quality. History of shift work schedules is associated with increased rates of hypertension. Shift work disrupts sleep, but further longitudinal studies are needed to determine if sleep quality mediates the association between shift work and hypertension. Il existe relativement peu d’études en population explorant le lien entre le travail par quarts et l’hypertension, ainsi que les mécanismes en cause. Notre étude avait pour but de déterminer si les antécédents de travail par quarts sont associés à une augmentation du risque d’hypertension chez les travailleurs adultes, et si la qualité du sommeil influe sur cette relation. Nous avons mené une étude de cohorte en population à partir des réponses d’Ontariens de 35 à 69 ans obtenues dans l’Enquête sur la santé dans les collectivités canadiennes de 2000-2001, qui ont été couplées aux données administratives en santé de l’Institute for Clinical Evaluative Sciences. Notre échantillon comprenait les répondants qui occupaient un emploi et n’avaient jamais reçu de diagnostic d’hyperte